Covalent Organic Framework @ Magnetic Carbon Nanotube Composite Rapidly Prepared by Mechanochemical Method for Sensitive Determination of AFB1 in Real Sample

Aflatoxin B 1 (AFB 1 ), a potent hepatocarcinogen, continually poses a serious threat to food safety and public health owing to its stability and propensity for bioaccumulation within the food chain. Monitoring its trace levels across various food matrices remains challenging, necessitating highly efficient and selective sample pretreatment materials. In this study, a novel covalent organic framework-based magnetic composite (3D-N/OCNS@TpPa-1) was rapidly synthesized via a solvent-free mechanochemical method within 30 min. The mechanochemical grinding method enabled not only the rapid and green synthesis of the COF but also its immediate integration with a carbon matrix. This composite strategy was specifically designed to mitigate the common challenges of COF aggregation and poor dispersibility. When employed as a solid-phase extraction sorbent, it demonstrated rapid adsorption/desorption kinetics (10 min and 8 min, respectively) and high affinity for AFB 1 . Coupled with HPLC-FLD, the method enabled the sensitive detection of AFB 1 across a complete food chain transmission pathway—corn, corn oil, chicken, and human plasma—with a wide linear range (0.25–250 μg·kg⁻ 1 ), a low detection limit (10 ng·kg⁻ 1 ), and high precision. The study not only provides a robust and green analytical approach for tracing AFB 1 propagation in agri-food systems but also highlights critical control points for intervention in food safety management.